CEREBELLUM

Presented by:-Mr. Suresh Kumar SharmaRN, ACCN, MSN(PSYCHIATRY)

BY

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DIVISIONS OF THE BRAIN

Forebrain Midbrain Hindbrain

CerebrumThalamus

Hypothalamus

Cerebral peduncleTectum

Brainstem

CerebellumPons

Medulla Oblongata

Sagittal View of the Brain3

FUNCTIONAL REGIONS OF THE BRAIN

The Cerebrum The Cerebellum The Brain Stem

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ANATOMY OF THE CEREBRUM

Cerebral Hemispheres(View from Above)

LeftRight5

FUNCTIONS OF THE CEREBRUM

Frontal lobe:•Voluntary movement•Higher intellectual functions

Temporal lobe:•Speech & Sound•Complex visual perceptions

Occipital lobe:•Vision

Parietal lobe:•Sensory processes•Attention•Language

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CONTRALATERAL FUNCTION OF THE CEREBRUM

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ANATOMY OF THE CEREBELLUM

1. Left Cerebellar Hemisphere

2. Right Cerebellar Hemisphere

3. Vermis

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3

Spinal cord

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CEREBELLAR FUNCTIONS

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ANATOMY OF THE BRAINSTEM

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FUNCTION OF THE BRAINSTEM

Midbrain:•Visual & auditory processing and reflexes•Fine-tuning of voluntary movements

Pons:•Relay station for cerebellum•Control of sub-conscious movement

Medulla Oblongata:•Control of cardiovascular functions•Control of respiration•Control of gastrointestinal functions

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CEREBELLUMCEREBELLUM

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GROSS ANATOMY OF CEREBELLUMGROSS ANATOMY OF CEREBELLUM

Location: The term cerebellum is from

“Latin meaning” the little brain.

part of the hindbrain situated in the posterior cranial fossa.

behind the Pons and medulla oblongata, separated from two structures by the cavity of fourth ventricle.

It is covered by tentorium cerebelli and is connected to brain stem by three cerebellar peduncles.

In adults the weight ratio between cerebellum and cerebrum is 1:10,Infants 1:20

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Consists of two laterally, large hemisphere which are united by midline vermis.

Cerebellar surface is divided by numerous curve transverse fissures giving it a laminated appearance

One conspicious fissure “horizontal fissure" extends around dorsolateral border of each hemisphere from middle Cerebellar peduncle to vallecula, separating superior and inferior surface

Horizontal fissure

Vermis

Hemisphere

Superior surface

Anatomy of cerebellum......contd.

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The deepest fissure in the vermis is primary fissure, which curves ventrolaterally in the superior surface of the cerebellum to meet horizontal fissure.

Primary fissure divides the cerebellum into anterior and posterior lobe.

Primary fissure

Anterior lobe

Posterior lobePrimary fissure

External surface of cerebellum

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Horizontal fissure

verm

is

Primary fissure

Anterior

lobe

Posterior lob

e

Hemisphere

External surface of cerebellum

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Fourth ventricle

Arbor vitae cerebelli

Arbor vitae •In Latin “ tree of life” it is the white matter of the cerebellum.

•It is so called because of the tree like appearance.

•It brings sensory and motor sensation to and from cerebellum.

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Vermis

Hemisphere

Parts of the cerebellum

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LOBES OF CEREBELLUMDivisions of lobesAnatomical

Flocculonodular lobe

Anterior lobe

Posterior lobe

Anterior lobe

Posterior lobe

Flocculonodular lobe

Inferior surface

Superior surface

Anterior lobe

Posterior lobe19

Functional(Evolutionary)

Paleocerebellum

Neocerebellum

Archicerebellum

Division of lobes…..contd.

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Archi-cerebellum posterior lobe (Vestibular part) •It is formed of the flocculo-nodular lobe + associated Fastigial nuclei, lying on inf. Surface in front of postero-lateral fissure. •Embryo logically, it is the oldest part of cerebellum. •It receives afferent Fibres. From vestibular apparatus of internal ear Via vestibulo-cerebellar tracts. •It is concerned with equilibrium

Neocerebellum

Archicerebellum

Paleocerebellum 21

Paleo-cerebellum (spinal part) •it is formed of midline vermis + surrounding paravermis + globose & emboliform nuclei.

•It receives afferent proprioceptive impulses from Ms.& tendons Via spinocerebellar tracts (dorsal & ventral) mainly.

•it sends efferent to red nucleus of midbrain.

•it is concerned with muscle tone & posture.

Paleocerebellum

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Neo-cerebellum (cerebralpart) •It is the remaining largest part of cerebellum.•It includes the most 2-cerebellar hemispheres + dendate nuclei.•It receives afferent impulses from the cerebral cortex + Pons Via cerebroponto-cerebellar pathway.•it sends efferent to Ventro lateral nucleus of thalamus.•it controls voluntary movements (muscle coordination).

Neocerebellum

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ArchicerebellumNodulus

Archicerebellumflocculus

Palaeocerebellum

Neocerebellum

Spinocerebellum

Pontocerebellum

Vestibulocerebellum

Summary of classification

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Classification by Classification by phylogeneticphylogenetic

Ontogenic developmentOntogenic development• ArchicerebellumArchicerebellum• PaleocerebllumPaleocerebllum• NeocerebellumNeocerebellum

Classification by Afferent Classification by Afferent ConnectionConnection

• VestibulocerebellumVestibulocerebellum•SpinocerebellumSpinocerebellum•Ponto cerebellumPonto cerebellum

Classification by Efferent Classification by Efferent Connection Connection

•VermisVermis•Paravermis RegionParavermis Region•Cerebellar HemisphereCerebellar Hemisphere

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INTERNAL STRUCTURE:-INTERNAL STRUCTURE:- Cerebellum consists of outer

layer of grey matter known as cortex and inner layer of white matter known as medulla.

The medullary core is composed of incoming and outgoing fibres projecting to and from the Cerebellar cortex.

Medullary core also contain the nucleuses of the cerebellum which are four in number.

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Cortex Medulla Structure of cerebellum

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Structure of Cerebellar……contd.Cerebellar Cortex:- Cerebellar Cortex:-

Molecular LayerMolecular LayerPurkinje Cell LayerPurkinje Cell LayerGranular LayerGranular Layer

Corpus Medullare (Medullary Center)Corpus Medullare (Medullary Center)

Deep Cerebellar Nuclei:-Deep Cerebellar Nuclei:-Fastigial NucleiFastigial NucleiNucleus InterpositusNucleus InterpositusEmboliform NucleusEmboliform NucleusGlobose NucleusGlobose NucleusDentate NucleusDentate Nucleus

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Dentate nucleus

Emboliform nucleus

Globose nucleus

Fastigial nucleusNucleus Interpositus

Deep nucleuses of cerebellum

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White matter of the cerebellum

Consists of three types of nerve fibres in the white matter

A.Axons of purkinje cells The only axons to leave Cerebellar cortex to end in deep Cerebellar nuclei specially dendate nucleus.

B.Mossy fibres They end in the granular layer.

C.Climbing fibres They end in the molecular layer

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The internal circuity of cerebellum:- Don't leave the cerebellum, interconnect different regions of cerebellum. Some connect the same side. Some connect the two Cerebellar hemisphere

The Cerebellar efferent via middle Cerebellar peduncle(MCP) and inferior Cerebellar peduncle (ICP)

The Cerebellar afferent via superior Cerebellar peduncle(SCP) and from Fastigial from inferior Cerebellar peduncle(ICP)

White matter of cerebellum

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The cerebellum is connected toBrain stem by three peduncles

Midbrain Middle Cerebellar

peduncle

PonsInferior Cerebellar peduncle

Medulla oblongata

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Superior Cerebellar peduncle

Peduncles of the cerebellum

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Fibres entering and leaving through Cerebellar peduncles

1.Superior cerebellar peduncle

A.Fibres entering the cerebellum 1. Ventral spino-cerebellar tract 2. Rostral spino-cerebellar tract 3. Tecto-cerebellar fibres 4. Rubro-cerebellar fibres 5. Trigemino-cerebellar fibres 6. Hypothalamo-cerebellar fibres 7. Coerulo-cerebellar fibres

B.Fibres leaving the cerebellum 1. Cerebello-rubral fibres 2. Cerebello-thalamic fibres 3. Cerebello-reticular fibres 4. Cerebello-olivary fibres 5. Cerebello-nuclear fibres 6. Some fibres to hypothalamus and thalamus

Superior cerebellar peduncle

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2.Middle cerebellar pedunclePontocerebellar fibres

3.Inferior cerebellar peduncle

A.Fibres entering cerebellum 1. Posterior spino cerebellar tract 2. Cuneo-cerebellar tract 3. Olivo-cerebellar fibres 4. Reticulo-cerebellar fibres 5. Vestibulo-cerebellar fibres 6. Anterior external arcuate fibres 7. Fibres of striae medullaries 8. Trigemino-cerebellar fibres

B.Fibres Leaving the cerebellum 1. Cerebello-olivary fibres 2. Cerebello-vestibular fibres 3. Cerebello spinal and cerebello reticular fibres

Middle cerebellar peduncle

Inferior cerebellar peduncle

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CT SCAN OF BRAIN WITH CEREBELLUM

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MRI OF BRAIN WITH CEREBELLUM

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Blood supply to brain

• Arch of aorta1. Brachiocephalic trunk

i. right common carotid artery

2. Left common carotid artery

3. Left subclavian artery

• right common carotid artery1. External carotid artery

2. Internal carotid artery

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Blood supply to brain• Anterior cerebral arteries –2• Internal carotid arteries –2• Anterior communicating artery-1• Posterior communicating artery-1• Posterior cerebral arteries -2• Basilar artery-2

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Circulus arterious(circle of Willis)

circle of Willis

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Blood supply to cerebellum• Superior surface of cerebellum – superior

Cerebellar branches of basilar artery(SCA)

• Inferior surface– Anterior part -(AICA)

• Anterior inferior Cerebellar

branches of basilar artery

– Posterior part- (PICA)• Posterior inferior Cerebellar• branches of basilar artery

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Functions of cerebellum

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Maintenance of EquilibriumMaintenance of Equilibrium - balance, posture, eye movement - balance, posture, eye movement

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Motor Leaning – Motor SkillsMotor Leaning – Motor Skills

Coordination of half-automatic movement Coordination of half-automatic movement of walking and posture maintenanceof walking and posture maintenance - posture -gait - posture -gait

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Adjustment of Muscle ToneAdjustment of Muscle Tone

,

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Cognitive FunctionCognitive Function

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CEREBELLAR FUNCTION TEST• FINGER TO FINGER FINGER TO NOSE

TEST TEST

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CEREBELLAR FUNCTION TEST• ROMBERG TEST TANDOM TEST

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Ataxia:Ataxia: incoordination of movementincoordination of movement - decomposition of movement- decomposition of movement - dysmetria, past-pointing- dysmetria, past-pointing - dysdiadochokinesia- dysdiadochokinesia - rebound phenomenon of Holmes- rebound phenomenon of Holmes - gait ataxia, truncal ataxia, titubation- gait ataxia, truncal ataxia, titubationIntention TremorIntention TremorHypotonia,Hypotonia, NystagmusNystagmus

Archicerebellar Lesion: Archicerebellar Lesion: medulloblastomamedulloblastomaPaleocerebellar LesionPaleocerebellar Lesion: gait disturbance: gait disturbanceNeocerebellar LesionNeocerebellar Lesion: hypotonia, ataxia, tremor: hypotonia, ataxia, tremor

Syndromes

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Cerebellar Cerebellar Ataxia Ataxia

Ataxic gait and position: Ataxic gait and position: Left cerebellar tumorLeft cerebellar tumor

a. Sways to the right ina. Sways to the right in standing positionstanding position

b. Steady on the b. Steady on the right legright leg

c. Unsteady on the c. Unsteady on the left legleft leg

d. ataxic gaitd. ataxic gait

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Cerebellar Cerebellar Medulloblastoma Medulloblastoma

Cerebellar tumors on Cerebellar tumors on

vermisvermis

- Truncal Ataxia- Truncal Ataxia

- Frequent Falling- Frequent Falling

The child in this picture:The child in this picture:

- - would not try to stand would not try to stand unsupportedunsupported

- would not let go of the - would not let go of the

bed railbed rail if she was stood on the if she was stood on the floor.floor. 53

.

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NOW TIME FOR ASSIGNMENT

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WRITE DOWN DIFFERENT DISEASES RELATED TO THE CEREBELLUM FUNCTION LOST???????